I’m not sure, but I think this might be the first time I’ve photographed a butterfly caterpillar. Not a bad subject to start with, as few butterflies have caterpillars that are more colorful than the Gulf Fritillary, Agraulis vanillae. A common resident in the southern states and further south, this member of the nymphalid subfamily Heliconiinae is less commonly encountered in Missouri—in fact, I had never seen (or at least noticed) these caterpillars before encountering a few feeding hungrily on the foliage of maypop (Passiflora incarnata) growing in a city park in Missouri’s southeastern lowlands. While the stunning colors of these caterpillars are a delight to human eyes, their function, as in most butterfly caterpillars, is to advertise the unpalatability of their toxin-laced bodies. In the case of this species, the toxins include cyanogenic glycosides that the larvae sequester from the tissues of their host plants (ironically these compounds are supposed to serve the same protective function for the plant that produces them, but butterflies have become master specialists at evolving mechanisms to sidestep toxic impacts).

According to my friends Richard & Joan Heitzman, long-time students of Missouri Lepidoptera, this species is a sporadic migrant that occasionally forms summer colonies in Missouri, especially in the western half of the state, until the first hard freeze destroys the colony (Heitzman & Heitzman 1987).

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About Ted C. MacRae

Ted C. MacRae is a research entomologist by vocation and beetle taxonomist by avocation. Areas of expertise in the latter include worldwide jewel beetles (Buprestidae) and North American longhorned beetles (Cerambycidae). More recent work has focused on North American tiger beetles (Cicindelidae) and their distribution, ecology, and conservation.

As fritillaries go, Gulf Fritillaries are pretty distinctive. Every now and then we get one in Colorado, but alas, no passionflowers = no caterpillars (I’m not indifferent to adult butterflies, but I have to admit that caterpillars are much more interesting.

We have several (three I believe) wild spp of Passiflora in AZ, but the Gulf Fritillaries really took off after there were more and more gardens with imported plants. This year I saw about twenty very fresh looking individuals in late January in a downtown residential area. No idea whether they emerged then? They seem to winter usually just fine here, I don’t remember whether the popoulations took a hit in 2010 when out temps dipped into the single didgits for several days. Right now they are flying in all canyons that have any flowers (water) left.
Dave Wagner got me into collecting cats for his next book and photographing them – lots of interesting stuff!

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